#include <iostream>
int porrango (int n1, int n2, int aux);
using namespace std;
int main()
{
    cout<<porrango(2,5,1);
    return 1;
}

int porrango (int n1, int n2, int aux)
{
    while(n1<=n2)
    {
        aux=aux*n1;
        n1++;
    }
    return aux;
}
